Heretofore, various proposals have been made for an electric wire arrangement of a vehicular panel that uses a wire harness (see JP H01-067809 A). A vehicular panel having such a structure according to a conventional example is illustrated in FIG. 12. In FIG. 12, a plurality of electric components 101 are installed on the surface side of an instrument panel 100 as the vehicular panel according to the conventional example. The instrument panel 100 is composed of a panel body 100A and an outer layer 100B arranged on the surface side thereof. A wire harness WH is wired on the back side of the instrument panel 100. Electric connections between the electric components 101 are made by the wire harness WH.